


What Am I To You?

by CaptainGogurt



Category: Gravity Falls
Genre: Confession, F/M, Holiday, Incest, NSFW, Oral Sex, Slow Burn, pinecest - Freeform
Language: English
Status: Completed
Published: 2020-12-09
Updated: 2020-12-09
Packaged: 2021-03-10 00:48:24
Rating: Mature
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 2,403
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/27975380
Author URL: https://archiveofourown.org/users/CaptainGogurt/pseuds/CaptainGogurt
Summary: It's the holiday season and Dipper had planned on making sure to enjoy it with his sister Mabel; however, he didn't plan for her to bring over her college boyfriend. Tensions rise as Dipper refuses to have any holiday cheer whilst watching her sister and boyfriend fawn over each other, causing the disgruntled brother to lash out during dinner. Leaving the dinner table in a huff, Mabel follows after her brother to try and calm him down and figure out why he's being such a grinch.
Relationships: Dipper Pines & Mabel Pines, Dipper Pines/Mabel Pines
Comments: 1
Kudos: 32





	What Am I To You?

**Author's Note:**

> A/N: Both of the twins are in college and 21 years of age.

“Dipper...” a voice spoke.

“Dipper.” it repeated.

“Dipper!” the voiced raised in frustration as the sound of a door was slammed shut as she entered the all too familiar room.

“Dipper! Mason! Pines!” the voiced yelled, completely adamant on having her voice heard. To their surprise, it worked, as the shaggy-haired man turned his attention to them.

“Don’t call me that! You know how much I hate that name!” he yelled in response. “And can you do me a favor and just... leave me alone?” the aggression in his voice quickly subsiding.

“Not until you tell me why you’ve been acting like such a major buttface all night!” they responded.

“Wha- no I haven’t!” Dipper hesitantly retorted.

“Oh yeeeaaah. No. You’re toootaaally riiight, Dip-Dop. Golly gee. Whatever was your dear sweet sister thinking?” her sarcasm oozing out with every word, “Glad to see you’re acting completely normal!”

“You can drop the sarcastic tone, Mabel.” Dipper exhaled.

“CAN I?” she continued, “I’m sorry that you THINK I’m being sarcastic- which is pretty rich coming from you, Mr. ‘NormalGuyWithNoAttitide” Pines!” the sarcasm shifting to a rant.

“Okay, okay, I get it. Let’s just drop it-“ cutoff by his sibling.

“I can ignore you not giving me a hug after driving six and half hours to see you for the holiday. Dismiss the snide comments you made about my life choices- about my BOYFRIEND-“ she continued.

“I’m serious, Mabel, drop it-“ his words were cut off again.

“WHO, might I remind you, is still downstairs in the dining room wondering why the heck my brother hates him so much when you BARELY even know him!” Mabel blurted out in a quick fit of anger.

“MABEL!” he shouted.

“YEAH, THE TRUTH SUCKS DOESN’T IT!?” she shouted back.

“It SUCKS having my own twin sister stand here and accuse me of acting like a complete ass all because she THINKS I hate her stupid boyfriend.” a slight voice crack could be heard in between Dipper’s response.

“OH. I KNOW YOU DO!” she blurted out.

“Anytime he spoke, moved or even showed me the slightest bit of affection- you acted like you wanted to toss him all the way to Timbuktu!” she continued. “Seriously! What’s going on in that big brain of yours, Dipper? This isn’t like you. You’re acting like my last ex-boyfriend when he found I was dating Joshua from my Art Appreciation... course...” her rant slowly came to an abrupt stop as the hamster in her head began running on its wheel.

An air of silence amongst them slowly dissipated the yelling echoing within their room. In this moment, Dipper felt every part of his being tense up as his mind screamed to run away, to shut out his sister, to pretend that the truth wasn’t coming to light. He had nothing to say, but his distraught face said everything.

“Dipper...?” she spoke, “Do you... have a thing... for me?” awkwardly questioning, before composing herself, “Dipper. Are you acting this way because you like me and are jealous of my boyfriend?”

His eyes surveyed around the room to avoid his sister’s gaze, but no avail did it last for long. “What...? N- No...! Eugh! Why... Why on earth would you come to that conclusion!? I mean... yeah, I love you- but like a sibling would! Not in a gross romantic way!” The more Dipper talked, the worse his stammer became. Fumbling over his words only made the nervous man a sweating mess.

Mabel, on the other hand, looked completely unfazed by her brother’s reaction and took a couple steps forward reiterating, “Dipper. Do you like me?”

Fear slowly overtaking his mind, Dipper took a couple steps backwards to widen the gap between them. “I- I told you... it’s not- it’s not like that, Mabel...”

A couple steps forward from Mabel. “So then, what’s the truth? Why else would you be acting like this?”

Trying to take another step back, Dipper felt a bump against his back as he had cornered himself to the wall. “Th- That is the truth...!” His heart rate quickening with every passing second.

Mabel stepped towards her panicking brother until they were mere inches away from one another. Hoping that this level of closeness would prevent Dipper from trying any sort of means to avoid eye contact or her question. “Dipper. Look at me.” She spoke.

“Please...” he pleaded, “Don’t do this-“

“Dipper.” she cut off, “Look at me.” her voice was stern and persistent in getting her way.

Dipper felt the room fading into nothingness as his focus slowly turned towards Mabel’s gaze. He could feel the onset of tears welling up inside him. “I...”

“Dipper. Do you like me?” she questioned once more, but in a softer tone.

“OKAY, YES, I LIKE YOU.” Unable to hold himself back anymore.

“I can’t explain- err... I’d rather not explain it, but these feelings inside of me are weird!” he continued, “I thought it was just me being an overprotective brother at first... but the more you went out and dated people, the more uneasy I became about it. I tried to let it go- to let these emotions about you go, but I couldn’t! I just couldn’t! Every time I think about you, I can’t help but feel drawn to that annoying carefree spirit of yours o- or how beautiful you look every time you bring out some wacky new design to show me and it makes it worse on me because I fall harder in... in... IN LOVE WITH YOU!”

He couldn’t stop himself. The floodgates were open. 

“I tried everything. I tried dating others too and I just felt... empty. Like there was no point in trying to build a romantic relationship with them. And... and every time... and every time I think about you I just...” Tears began to fall down his cheeks.

“Oh man... I’m so sorry... I’m sorry... I... I’m disgusting... I’m a disgusting, terrible, sibling that can’t stop pining after his own sister... I’m so sorry...” Dipper cried.

Mabel listened to her brother’s confession as he finally came clean. Honestly, she had never thought much about the implication that her brother would end up developing romantic feelings for her. She was, to say the least, unsure how to immediately respond, but after a few moments passed she spoke.

Lifting her hand up to his face, Dipper braved himself for what he perceived to be an oncoming slap from Mabel. His tensed up body slowly relaxed itself as the feeling of her hand gently wiped away the tears on his face. “So that’s you’ve been acting so weird lately... well, weirder than normal.” She stated.

Taking her hand from his face, she quickly flicked her brother’s nose.

A grunt escaped her brother’s mouth as he quickly covered his mouth and nose with his hand. “OWW!!! Mabel-“

“That still doesn’t excuse the way you’ve been acting tonight, buster brown!” she scolded. 

“You mean to tell me that you’ve been actin’ like a sour-puss because you’ve got a thing for me!? I thought it was because you hated me or something, but nooooope, you just gots the hots for me.”

Dipper removed his hands from his face. “Can you stop repeating that, it sounds weird hearing you say it!” he responded.

“WEIRD???” she exaggerated. “Bro, we literally fought a demonic-triangle bent on drowning the world in his own sick weirdness and you’re telling me that THIS is weird to you???” 

“It’s WEIRD because I don’t know if you’re upset, grossed out, or hate me because of this- mmmph!” Dipper was cutoff by a pair of soft hands squishing his cheeks together and making his face look pouty.

“Duuuh, I’m Dipper and I think having feelings for my sister is weirded than having my body possessed by a talking triangle. Buh-buh-buh!” She playfully mocked.

Moving her hands away from his face, Dipper’s sad demeanor quickly shifted to one of concern. “Can you PLEASE take this seriously, Mabel! You have no idea how badly this is affecting.”

“I can’t take this seriously when this whole night could have been avoided if you just would’ve said this from the start!” She yelled. “Seriously, Dipper? You think THIS is what would have caused me to hate you? Pfffftt- as if!” She scoffed off.

“Wait... what?”

Taking a long exhale, Mabel rubbed the side of her arm as she spoke. “Look, Dipper, I love you and will- as an older sister and a best friend. Nothing will ever change that, but you gotta be more open about what’s cookin’ in that big brain of yours, okay?”

Looking into his sister’s eyes, Dipper could tell she was honest in the words she said. With a slow nod of approval, Mabel smiled and latched onto her brother for a loving sibling hug that quickly became an awkward sibling hug as Mabel felt something poking against her thigh.

“Wow... you really do have a thing for me, huh?” She awkwardly spoke.

It didn’t immediately occur to Dipper what she meant as his mind was too busy coming down from the fright of earlier, but now he could feel something pulsating below. “Oh no...” he said before breaking away from the embrace.

“Oooooh no, no, no, no, no-“ stammering once again. “Listen... I just... The confession got me all emotional and... you were so close that I just... well THIS happened, but-“

“Dipper!” She yelled. “Dude, chill, it’s cool.”

“How is THIS cool!?” he meekly yelled back trying his best to hide his shame.

“Well, for one, I know that awkward boners are thing, especially when my boyfriend gets them from time to time.” She snickered.

Dipper had almost forgot about Mabel’s boyfriend until now, but it only caused the situation to be even more awkward than before. “Not helping, Mabel!”

“What I’m saying is that it’s normal that... uh- this happened. ‘Specially since my bro-bro is pretty horny on main for me, hehe.” She chuckled a bit to herself.

“But... uh, you should probably get that taken care of. Don’t want everyone downstairs to know we have a special sixth guest. Isn’t that right ‘Lil’ Dipper’~ Hehe.”

“You’re REALLY not helping- AND DON’T CALL MY JUNK THAT!” his voice cracking more than before.

“Sorry, I couldn’t help myself- but, yeah, you seriously gotta put that thing away or we’ll get hounded by mom and dad.” Mabel stated.

“Yeah, well, I would but it’s kind of hard to do that while you’re still in here...” he replied.

“Hehe... yeah it is~” she jokingly winked.

“Not funny!” he yelled.

“Okay, okay, sorry. Look how about this. Since you technically got all hot and bothered because of me, how about I help you take care of this?” she offered.

“I- huh?” Dipper thought he was hearing things and needed clarification by what his sister meant.

“Let me make you cum.” she said with full conviction.

Dipper swore he could feel the precum staining the inside of his shorts after heard Mabel say that so nonchalantly. “I... you... WHAT!?”

An exhale left Mabel’s mouth. “Look. You can either play Meat Beat Mania by yourself or we can play co-op mode and get it done faster. Your choice.”

A few moments passed, but Dipper’s rationality was no longer in effect as he began unbuckling the belt to his shorts and letting them drop to the ground. Taking a deep breath before taking off his boxers and placing them on the ground as well.

“Woah momma!” She said in surprise. 

“What!? What!? Does it look weird! Does it smell? I- I took a shower, but I know I sweated a bit earlier and-aaah~!“ he started on his usual tangents, unaware that Mabel had already knelt down on the ground and began touching his member. “Mabel... wait...”

Mabel, being completely amazed by the sight her brother’s junk. She couldn’t help but touch it to feel what she was seeing. “I guess you were right. I shouldn’t call him “lil’ dipper” huh?” She lightly snorted at the reminder of the name she gave him.

“M- Mabel... your hand... it... ah...” The words wishing to escape her brother’s mouth seemed all for naught as his sentences quickly turned into gasps and moans of pleasure as he felt the nimble fingers of his sister’s hand wrapped around the shaft of his cock. Stroking him ever so slowly, Dipper felt as if he were about to explode any second from just this small amount of pleasure from the woman he had thought so much about throughout the prior years.

“Mabel... Mabel... I’m...” Dipper moaned trying to warn his sister about his oncoming release.

“Hey, Dipper, guess what?” Mabel asked.

“W- Wha-“ he spoke before immediately being cutoff by an action his sister pulled.

“Bwomp~” she sounded before kissing the head of her brother’s member as she slowly let it pass between her lips. Her tongue coiling around the tip in succession with each bob of her head.

The warm and wet sensation Dipper felt was unimaginable and quickly drove him over the edge as he quickly lost all control over himself and released the hot wave of euphoria that had built up inside of him for so long.

Feeling the unexpected spurt of her brother inside her mouth made Mabel wince a bit, but in the end she kept him inside and swallowed every last drop of what her brother released. Making sure to lick off any excess cum to cause Dipper to spasm from the overstimulation.

“AH. AH. AH. S- STOP. T- TOO MUCH...” he pleaded.

Even though Mabel removed her mouth from her brother’s cock, she couldn’t help but think to herself how much she wanted to keep teasing him after hearing those desperate moans of his, but she shook away that desire. “Better?” She asked.

Dipper’s heart was about to jump out of his chest at the situation that just unfolded. Several questions invaded his mind as what to say and what to do, but all he could respond with before looking down at his sister’s smiling face was, “M- Much better.” 

“Good.” standing up from the ground and adjusting her outfit, “Alright, I’m gonna head back downstairs so no one wonders why we’ve been gone for so long.” Opening the door, Mabel turned around to her brother once more.

“Oh, and Dipper. FYI. You should cut back on the salty snacks and Pitt Cola~”


End file.
